As is well known in the medical field, there is an increasingly occurring problem where connective tissue, such as tendons and ligaments, tear or detach from the associated bone. While this invention is not limited to the method of incisions used in this type of operation, there is a trend to use arthroscopic surgical techniques rather than cutting large incisions in the tissue of the patient for performing the reattachment operation in this medical procedure. A typical problem that is the concern of this invention, although not the only one, is the tear or detachment of the soft tissue in rotator cuff as to where the supraspinatus tendon separates from the humerus. In this type of medical procedure the advent of the knotless suture has played an important roll in allowing the surgeon to perform this type of operation using arthroscopic techniques.
Unfortunately, the known knotless types of suture anchors that are capable of supporting the tendon to the bone is not efficacious for certain types of patients or where the surgeon inadvertently or aggressively removes the outer cortical layer of the bone while preparing the area of concern during the operative procedure or an anchor has been removed from the bone cavity and another anchor is intended to replace it. In these instances the bone structure is not sufficiently strong to hold the knotless suture types of anchors and under the circumstances the anchor or suture anchor will avulse from the bone. This failure mode is more common in the osteoporotic bone found in older patients. Obviously, the non screw-in types of anchors have a higher propensity to avulse from the bone than the screw type of anchor. That's because the knotless devices require the sutures to be placed through the soft tissue and threaded through the anchor prior to placement of the anchor into the bone. The knotless suture typically either have wings that expand inside the bone or have an asymmetrical shape that, under load, will toggle inside the bone such that it is captured below the bone surface. These anchors have less surface area in contact with the bone than do the screw type of anchor, so that suture anchors avulsion from the bone is more likely to occur.
The medical industry has seen a number of devices that have attempted to solve the problem of prematurely avulsion of anchors from the bone. For example, U.S. Pat. No. 5,728,136 granted to Thal on Mar. 17, 1998 entitled “KNOTLESS SUTURE ANCHOR ASSEMBLY” describes a knotless suture anchor that is in the form of a spike that is inserted in a ratcheting manner into a sleeve that was previously inserted into the cavity of the bone. The spike carrying the suture is inserted through the tissue being fastened to the bone before being attached to the anchoring sleeve.
U.S. Pat. No. 6,689,135 granted to Enayati on Feb. 10, 2004 entitled “EXPANDABLE BONE FASTENER AND INSTALLATION TOOL” describes a device similar to the Thal structure that includes a sleeve mounted in the bone cavity and a pin that is inserted into the sleeve. The pin includes barbs or wings that expand into slots formed in the sleeve and the suture is attached to the pin.
U.S. Pat. No. 5,472,452 granted to Trott on Dec. 5, 1995 entitled “RECTILINEAR ANCHOR FOR SOFT TISSUE FIXATION” relates to a rectangular shaped inner member having a wave-like outer surface that fits into a rectangular opening formed into a rectangular shaped outer member such that when the inner member is inserted into the opening it forces wing-like elements formed on the outer member that are forced into the bone for holding the same into the bone cavity.
U.S. Pat. No. 5,584,835 granted to Greenfield on Dec. 17, 1996 entitled “SOFT TISSUE TO BONE FIXATION DEVICE AND METHOD, is another system intended to secure an anchor to the bone to avoid avulsion and includes a threaded outer member that is tapped into the bone cavity and an inner member that is either rectangular or circular shaped in cross section.
U.S. Pat. No. 5,013,316 granted to Goble et al on May 7, 1991 entitled “SOFT TISSUE ANCHOR SYSTEM” which describes a footing stud that is drilled into the bone and includes self tapping threads. The footing stud includes a cylindrical recess that accommodates a tack that includes a shaft with wing-like elements much in the shape of an arrow head. The point is inserted through the soft tissue and into the recess and at the opposite end of the shaft is a broad head with protruding spikes that are impaled into the soft tissue.
U.S. Pat. Nos. 6,616,665 and 6,569,188 granted to Grafton et al on Sep. 9, 2003 entitled “METHOD OF ROTATOR CUFF REPAIR” and on May 27, 2003 entitled “HEX DRIVE BIOABSORBABLE TISSUE ANCHOR”, respectively, disclose a headed bio-absorbable tissue anchor with a continuous thread spiraling around a tapering central core. A driver tool includes a distal end that fits into slots formed on the head for turning the threaded unit into the bone.
These referenced patents, which are incorporated herein by reference, describe the typical prior art devices of anchors that utilize sutures or flanges where the apparatus is designed so that the outer and inner components are specifically designed to mate with each other. Also shown in these prior art devices are anchors that are threaded to the bone and in some instances the anchors are of the knotless suture types. Hence, while it is fair to state that the prior art discloses anchors that are utilized to screw into the bone, these prior art types of devices are strictly anchors that are intended as a medical structure that is capable of being initially inserted into the bone for soft tissue attachment. None of these prior art devices are intended to solve the problem attendant from the occasion when the avulsion of a previously installed anchor from the bone of the patient occurs. As mentioned earlier, avulsion of the anchor from the bone typically occurs from osteoporotic bone found in older patients or where the surgeon aggressively removes the outer, cortical layer of the bone while preparing the area for soft tissue repair.
While the present invention utilizes the screw-in types of anchors that are described in the aforementioned patents, this feature of the invention is only utilized in the receptacle. This invention combines the effectiveness of these screw-in features with the convenience and efficaciousness of a knotless suture anchor. It is fair to state that this invention serves to obviate the avulsion problem and is different from the types of devices described in the above mentioned patents from both the structural design and the design philosophy as will become more apparent from the description to follow. Where the prior art devices are designed such that the inner and outer components are mutually dependent on each other, the present invention deviates from this philosophy and utilizes a commercially available knotless suture anchor that is susceptible to avulse from the bone under certain bone conditions and provides a receptacle that allows its use so as to obviate the avulsion problem. In accordance with this invention, the knotless suture anchor that is commercially available from The Anspach Effort, Inc. of Palm Beach Gardens, Fla., is an example of a commercially available anchor that is adapted to be utilized with the receptacle of this invention. It should be understood that other types of knotless suture anchors may also be utilized with this invention, as for example, the anchors available through Opus Medical, or Depuy Mitek and others. In accordance with this invention, two embodiments are presented and each of the embodiments utilizes the type of knotless suture described in U.S. Pat. No. 7,144,415, supra. In one embodiment, the receptacle includes outer threads that attach to the bone and the knotless anchor passes through a central bore and through the distal end where the suture anchor is deployed to impale the bone. In the second embodiment the knotless anchor is captured in a recess of the receptacle where the tips of the wings engage the inner surface of the central bore of the receptacle. With respect to the question of obviousness, it is noted that notwithstanding the fact that the tips of the wings of these commercially available anchors are relatively thin and fragile, they are intended to pierce or impale the bone structure and attach to the bone with sufficient strength to cinch the soft tissue to the bone by the suture attached thereto, it is hardly obvious to utilize these types of anchors where the wings are not utilized to impale the bone structure. Hence, according to one embodiment of the present invention the inner bore is necked down at the distal end that allows the winged portion of the anchor to pass therethrough while the locking portion is captured in the recess. Upon deployment, the wings are folded in half and each half moves toward each other in the shape of a “V” and impale the bone in the radial direction. In the second embodiment the impaling aspect of the anchor is not utilized to secure the anchor to the bone, but rather remain within the receptacle.
In this invention the receptacle for both embodiments includes outer threads that serve to tap the receptacle into the bone and includes a tool engaging portion that allows the surgeon to thread the screw-like receptacle into the bone. The receptacle includes a circular central recess opened at the proximate end for receiving the knotless suture anchor and an inner flange or projection that allows the wings of the anchor to pass there-through and prevent the anchor to retreat when the wings are deployed. In one embodiment, the diameter of the recess is such that the tip of each of the wings are forced to fold over itself that enhances the structural integrity of the unit so as to allow the surgeon to exert sufficient force to withdraw the suture in order to cinch the soft tissue to the bone while at the same time providing an anchor that obviates the avulsion problem. In the other embodiment, the wings are deployed and extend beyond the distal end of the central through bore of the bore and enter the bone to augment the holding force of the anchor/receptacle device. Obviously, this allows the surgeon to exercise his judgment as to which embodiment would be appropriate, namely whether to utilize the anchor without the receptacle or utilize the combined anchor/receptacle. This is in contrast to heretofore known systems where, if the receptacle cannot be utilized, the entire unit (the receptacle/anchor) is not usable.